Why curry doesn't work with :+

1

I was expecting the following to return a Proc:

:+.to_proc.curry.(10)

But it raises an error:

ArgumentError (wrong number of arguments (given 0, expected 1))

If we have a proc similar to :+:

add = ->(x,y){x + y}
add.curry.(10)

I get the expected Proc.

Why curry doesn’t work as I’m expecting with :+?